Polymerization of butadiene



Patented Nov. 25, 1947 2,431,403 roLvMERIzA'rroN oF BUTADIENE Herbert L. Johnson, Media, Hans G. Voelker,

Philadelphia, and Archibald P. Stuart, Norwood, Pa., assignors to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Di'awing. Application December 28, 1945, Serial No. 637,786

8 Claims.

This invention relates to the polymerization of butadiene and certain of its derivatives employing for this purpose a contact mass consisting essentially of a fused alumina to obtain materially higher yields of products, particularly dimer products, than have been obtained heretofore with other contact masses. More particularly, the invention relates to the treatment at an elevated temperature of butadiene, butadiene having one or two methyl groups, ormixtures of these compounds, in the presence of a contact mass consisting essentially of a fused alumina to obtain materially higher yields of polymeriza tion products, particularly dimer products, than have been heretofore obtained with other contact masses. A particularly important advantage and characteristic feature of the invention resides in the fact that with the use of a fused alumina as contact mass the course of the polymerization reaction can be directed, under certain hereinafter specified conditions, to yield predominantly the dimer products to the substantial exclusion of materials boiling either higher or lower than said product and in some instances to form no material boiling at a lower temperature than the dimer product.

Contact masses which have been employed homologues have been found to give yields of polymer products which are substantially lower than those which can be obtained employing a fused alumina according to this invention. Furthermore, the contact masses heretofore employed have been found not to exhibit the directive influence or effect obtained with fused alumina, as described above, namely that substantially all the product formed consists of the dimer product and especially that it ispossible to obtain the dimer product, under certain conditions, to the absolute exclusion of the formation of materials boiling lower than the boiling temperature of the dimer product. 1

Thus, according to the invention, there is provided a novel process for the treatment of a butadiene compound at an elevated temperature with a contact mass consisting essentially of a fused alumina to obtain yields of polymerization products which are substantially higher than any yields heretofore obtained, as well as'a process for the treatment of a butadiene compound at an elevated temperature and certain other conditions, hereinafter disclosed, to obtain high yields of substantially the dimer product and in some cases, under still more specific conditions, to obtain the dimer product to th absolute exclusion of any materials boiling lower than the boiling temperatureof the dimer product and to the substantial exclusion of materials boiling higher than the dimer product.

Herein and in the claims the term butadiene compound includes butadiene, butadiene having one or two methyl groups, or mixtures thereof. Since the invention is pre-eminently suited to the treatment of butadiene it will now be more fully described with reference thereto, particularly with respect to its polymerization or dimerization to vinylcyclohexene.

The temperature at which the contact mass is employed can be varied considerably. However, for the polymerization, generally, a temperature within the range 350 C.-450 C. will be employed. For the dimerization the temperature will be within the range 375 C.-425 0., and will be preferably about 400 C.

The pressure at which the polymerization or dimerization reaction is effected is important. For the polymerization reaction, generally, a pressure within the range atmospheric to about 200 lbs/sq. in. gauge will be employed. For the dimerization reaction a pressure within the range 15 lbs/sq. in. lbs/sq. in. will be employed and will be preferably about 35 lbs./sq. in.

Generally a rate within the range 2-8 grams/minute/IOO grams of contact mass will be employed for the polymerization reaction. For the dimerization reaction a rate within the range 3-6 grams/minute/IOO grams contact mass will be employed and the rate will be preferab within the range 4-5 grams/minute/IOO grams contact mass. 1

As stated, a characteristic feature of the invention is that it is possible under the herein disclosed conditions to substantially dimerize the charging material, that is, it is possible to polymerize to the dimer product with little or no formation of lower boiling materials or substantial formation of higher boiling materials. As a result of this characteristic of the invention high yields of products, particularly, the dimer products, can be obtained and on recycling any unconverted charging material these already high yields can be substantially increased since loss through undesirable materials boiling lower and higher than the desired products is greatly minimized.

As stated, the contact mass employed according to the invention is essentially fused alumina. A fused alumina which has been found suited to the practice of th invention is sold in the trade under the name Alfrax. Obvious y Particle sizes ranging from 4-5 mesh have been employed. Other mesh sizes can be employed 4 a temperature within the range 350 C.450 C. with a contact mass consisting essentially of fused alumina.

2. The treatment of a butadiene compound at the essential condition being good contact be- 5 a temperature within the range 350 C.-450 C. tween the butadiene compound and the contact and at a pressure within the range atmospheric masss t t t mass s l not cause to about 200 lbs/sq. in. with a contact mass contoo great a pressure drop through the conversion sisting essentially of fu ed lumi a, t Practical operation reasons. 3. The treatment according to claim 2 wherein In use, some coke or heavier polymer materials the compound is charged at a rate of 28-grams/- will eventually accumulate upon the contact minute/100 grams contact mass. mass. T s can e s y b b e o e p y 4. The treatment according to claim 2 wherein methods well known in the art and the mass can th but di n compound i b t i be used almost indefinitely. 5. The treatment of a butadiene compound at The following table illustrates results obtained a temperature within the range 375 C.-425 C. with contact masses other than fused alumina and at a pressure within the range 15 lbs/sq. in.- and with fused alumina. 75 lbs/sq. in. with a contact mass consisting Table Yields, Per Cent Tem llfs gt ii i 'r Contact Mass w?" sq. 1st? in. 100 ma s $35,3- my gfi v1.1 1. 33113 Recycle 53- gauge contact mass Bum cyclohub Ieye ovinylcycw vinylcyy diene ene exene hexene clohexme Activated Alumina (A1c0" Grade A 4-8 Mesh) 375 4.1 36.0 1.3 4.2 24.4 6.5 11.9 Do 400 60 5.1 21.4 9.9 1.2 26.2 1.5 58.7 Porous Clay Plate (10 Mesh) 375 60 5.0 68. 7 1.3 6. 4 v9. 6 15.3 86.0 Do 400 60 5.4 61.1 1.5 14.5 14.0 33.1 91.1 Fused Alumina (Alfrax"45 Mesh) 400 so as 34.9 3.0 37.6 14.2 66.8 89.7 Do 400 4.2 57.7 o 28.2 4.0 65.7 90.5

It can be noted at the outset that at temperaessentially of fused alumina at a charging rate tures within the range claimed herein activated within the range 3-6 grams/minute/IOO grams alumina gives extremely poor yields relative to 35 contact mass. those obtained with fused alumina. Even porous 6. The treatment according to claim 5 wherein clay plate, considered to be an efficient contact the butadiene compound is butadiene, the temmass, yields poor results relative to those obtained perature selected is about 400 C., the pressure with fused alumina. selected is about 35 lbs/sq. in. and the charging It is also to be noted, that owing to the characrate is 4-5 grams/minute/IOO grams contact mass. teristic feature of the invention, namely that 7. The treatment according to claim 2 wherein undesired products can be avoided, that the the butadiene compound is a methyl butadiene. recycle yields are substantially higher when using 8. The treatment according to claim 2 wherein fused alumina than the other contact masses. the butadiene compound is a dimethyl butadiene. This is a material and substantial improvement not foreseeable especially in view of the extreme- HERBERT L. JOHNSON. 1y poor performance of activated alumina. HANS G. VOELKER.

It will be obvious to those skilled in the poly- ARCHIBALD P. STUART. merization art that modification and variation are possible within the scope of the invention R F RENCES CITED the essence of whic is t butadiene The following references are of record in the pound can be polymerized, at elevated temperafil of this patent: tures employing a contact mass consisting essentially of fused alumina, in yields exceeding by UNITED STATES PATENTS such an amount the yields heretofore obtainable N b Name Date with other contact masses, and in certain circum- 2,355,392 Oberfefl Aug 8, 1944 stances without the formation of materials boil- 2,376,985 Voorhees Q May 29, 1945 ing at a temperature lower than the boiling em- 2,398,930 Gary Apr. 23, 1946 perature of the dimer product, as to amount to unpredictable results. FOREIGF PATENTS We claim: Number Country Dat 1. The treatment of a butadiene compound at 343,116 Gr t i in F b. 16. 1931 

